Multi-speed transmission

ABSTRACT

A transmission is provided having an input member, an output member, at least four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices include three clutches and three brakes actuatable in combinations of three to establish each of ten forward gear ratios and one reverse gear ratio.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/594,108 filed Feb. 2, 2012. The disclosure of the above applicationis incorporated herein by reference.

FIELD

The invention relates generally to a multiple speed transmission havinga plurality of planetary gear sets and a plurality of torquetransmitting devices and more particularly to a transmission having tenor more speeds, at least four planetary gear sets and a plurality oftorque transmitting devices.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A typical multiple speed transmission uses a combination of frictionclutches, planetary gear arrangements and fixed interconnections toachieve a plurality of gear ratios. The number and physical arrangementof the planetary gear sets, generally, are dictated by packaging, costand desired speed ratios.

While current transmissions achieve their intended purpose, the need fornew and improved transmission configurations which exhibit improvedperformance, especially from the standpoints of efficiency,responsiveness and smoothness and improved packaging, primarily reducedsize and weight, is essentially constant. Accordingly, there is a needfor an improved, cost-effective, compact multiple speed transmission.

SUMMARY

A transmission is provided having an input member, an output member,four planetary gear sets, a plurality of coupling members and aplurality of torque transmitting devices. Each of the planetary gearsets includes first, second and third members. The torque transmittingdevices are for example clutches and brakes.

In another embodiment of the present invention, the transmission has afirst, second, third and fourth planetary gear sets each having a sungear, a carrier member and a ring gear.

In still another embodiment of the present invention, the input memberis continuously connected for common rotation with the ring gear of thefirst planetary gear set.

In still another embodiment of the present invention, the output memberis continuously connected for common rotation with the carrier member ofthe fourth planetary gear set and the ring gear of the third planetarygear set.

In still another embodiment of the present invention, a firstinterconnecting member continuously interconnects the carrier member ofthe first planetary gear set with the sun gear of the third planetarygear set.

In yet another embodiment of the present invention, a secondinterconnecting member continuously interconnects the ring gear of thesecond planetary gear set with the ring gear of the fourth planetarygear set.

In yet another embodiment of the present invention, a thirdinterconnecting member continuously interconnects the carrier member ofthe second planetary gear set with the carrier member of the thirdplanetary gear set.

In yet another embodiment of the present invention, a fourthinterconnecting member continuously interconnects the ring gear of thethird planetary gear set with the carrier member of the fourth planetarygear set.

In yet another embodiment of the present invention, a first torquetransmitting mechanism is selectively engageable to interconnect thecarrier member of the third planetary gear set and the carrier member ofthe second planetary gear set with the sun gear of the fourth planetarygear set.

In yet another embodiment of the present invention, a second torquetransmitting mechanism is selectively engageable to interconnect the sungear of the third planetary gear set and the carrier member of the firstplanetary gear set with the sun gear of the fourth planetary gear set.

In yet another embodiment of the present invention, a third torquetransmitting mechanism is selectively engageable to interconnect thering gear of the first planetary gear set and the input member with thesun gear of the fourth planetary gear set.

In yet another embodiment of the present invention, a fourth torquetransmitting mechanism is selectively engageable to interconnect thering gear of the second planetary gear set with the stationary member.

In yet another embodiment of the present invention, a fifth torquetransmitting mechanism is selectively engageable to interconnect the sungear of the second planetary gear set with the stationary member.

In yet another embodiment of the present invention, a sixth torquetransmitting mechanism is selectively engageable to interconnect the sungear of the first planetary gear set with the stationary member.

In yet another embodiment of the present invention, the torquetransmitting mechanisms are selectively engageable in combinations of atleast three to establish a plurality of forward speed ratios and atleast one reverse speed ratio between the input member and the outputmember.

Further features, aspects and advantages of the present invention willbecome apparent by reference to the following description and appendeddrawings wherein like reference numbers refer to the same component,element or feature.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a lever diagram of an embodiment of a ten speed transmissionaccording to the present invention;

FIG. 2 is a diagrammatic illustration of an embodiment of a ten speedtransmission according to the present invention; and

FIG. 3 is a truth table presenting the state of engagement of thevarious torque transmitting elements in each of the available forwardand reverse speeds or gear ratios of the transmissions illustrated inFIGS. 1, 2 and 3.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

At the outset, it should be appreciated that the embodiments of themulti-speed automatic transmissions of the present invention have anarrangement of permanent mechanical connections between the elements ofthe four planetary gear sets. For example, a second component or elementof a first planetary gear set is permanently coupled to a thirdcomponent or element of the third planetary gear set. A first componentor element of the second planetary gear set is permanently coupled afirst component or element of the fourth planetary gear set. A secondcomponent or element of the second planetary gear set is permanentlycoupled to a first component or element of the third planetary gear set.A second component or element of the third planetary gear set ispermanently coupled to a second component or element of the fourthplanetary gear set.

Referring now to FIG. 1, an embodiment of a ten speed transmission 10 isillustrated in a lever diagram format. A lever diagram is a schematicrepresentation of the components of a mechanical device such as anautomatic transmission. Each individual lever represents a planetarygear set wherein the three basic mechanical components of the planetarygear are each represented by a node. Therefore, a single lever containsthree nodes: one for the sun gear, one for the planet gear carrier, andone for the ring gear. The relative length between the nodes of eachlever can be used to represent the ring-to-sun ratio of each respectivegear set. These lever ratios, in turn, are used to vary the gear ratiosof the transmission in order to achieve an appropriate ratios and ratioprogression. Mechanical couplings or interconnections between the nodesof the various planetary gear sets are illustrated by thin, horizontallines and torque transmitting devices such as clutches and brakes arepresented as interleaved fingers. Further explanation of the format,purpose and use of lever diagrams can be found in SAE Paper 810102, “TheLever Analogy: A New Tool in Transmission Analysis” by Benford andLeising which is hereby fully incorporated by reference.

The transmission 10 includes an input shaft or member 12, a firstplanetary gear set 14, a second planetary gear set 16, a third planetarygear set 18 and a fourth planetary gear set 20 and an output shaft ormember 22. In the lever diagram of FIG. 1, the first planetary gear set14 has three nodes: a first node 14A, a second node 14B and a third node14C. The second planetary gear set 16 has three nodes: a first node 16A,a second node 16B and a third node 16C. The third planetary gear set 18has three nodes: a first node 18A, a second node 18B and a third node18C. The fourth planetary gear set 20 has three nodes: a first node 20A,a second node 20B and a third node 20C.

The input member 12 is continuously coupled to the third node 14C of thefirst planetary gear set 14. The output member 22 is coupled to thesecond node 20B of the fourth planetary gear set 20. The second node 14Bof the first planetary gear set 14 is coupled to the third node 18C ofthe third planetary gear set 18. The first node 16A of the secondplanetary gear set 16 is coupled to the first node 20A of the fourthplanetary gear set 20. The second node 16B of the second planetary gearset 16 is coupled to the first node 18A of the third planetary gear set18. The second node 18B of the third planetary gear set 18 is coupled tosecond node 20B of the fourth planetary gear set 20.

A first clutch 24 selectively connects the second node 16B of the secondplanetary gear set 16 and the first node 18A of the third planetary gearset 18 with the third node 20C of the fourth planetary gear set 20. Asecond clutch 26 selectively connects the second node 14B of the firstplanetary gear set 14 and the third node 18C of the third planetary gearset 18 with the third node 20C of the fourth planetary gear set 20. Athird clutch 28 selectively connects the third node 14C of the firstplanetary gear set 14 and the input member 12 with the third node 20C ofthe fourth planetary gear set 20. A first brake 30 selectively connectsfirst node 16A of the second planetary gear set 16 and the first node20A of the fourth planetary gear set 20 with a stationary member ortransmission housing 50. A second brake 32 selectively connects thethird node 16C of the second planetary gear set 16 with the stationarymember or transmission housing 50. A third brake 34 selectively connectsthe first node 14A of the first planetary gear set 14 with thestationary member or transmission housing 50.

Referring now to FIG. 2, a stick diagram presents a schematic layout ofan embodiment of the ten speed transmission 10 according to the presentinvention. In FIG. 2, the numbering from the lever diagram of FIG. 1 iscarried over. The clutches and couplings are correspondingly presentedwhereas the nodes of the planetary gear sets now appear as components ofplanetary gear sets such as sun gears, ring gears, planet gears andplanet gear carriers.

For example, the planetary gear set 14 includes a sun gear member 14A, aring gear member 14C and a planet gear carrier member 14B that rotatablysupports a set of planet gears 14D (only one of which is shown). The sungear member 14A is connected for common rotation with a first shaft orinterconnecting member 42. The ring gear member 14C is connected forcommon rotation with the input shaft or member 12. The planet carriermember 14B is connected for common rotation with a second shaft orinterconnecting member 44. The planet gears 14D are each configured tointermesh with both the sun gear member 14A and the ring gear member14C.

The planetary gear set 16 includes a sun gear member 16C, a ring gearmember 16A and a planet gear carrier member 16B that rotatably supportsa set of planet gears 16D (only one of which is shown). The sun gearmember 16C is connected for common rotation with a third shaft orinterconnecting member 46. The ring gear member 16A is connected forcommon rotation with a fourth shaft or interconnecting member 48. Theplanet carrier member 16B is connected for common rotation with thefifth shaft or interconnecting member 52. The planet gears 16D are eachconfigured to intermesh with both the sun gear member 16C and the ringgear member 16A.

The planetary gear set 18 includes a sun gear member 18C, a ring gearmember 18B and a planet gear carrier member 18A that rotatably supportsa first set of planet gears 18D (only one of which is shown) and asecond set of planet gears 18E (only one of which is shown). The sungear member 18C is connected for common rotation with the second shaftor interconnecting member 44 and a sixth shaft or interconnecting member54. The ring gear member 18B is connected for common rotation with aseventh shaft or interconnecting member 56. The planet carrier member18A is connected for common rotation with the fifth shaft orinterconnecting member 52 and with an eighth shaft or interconnectingmember 58. The first set of planet gears 18D are each configured tointermesh with both the sun gear member 18C and the second set of planetgears 18E. The second set of planet gears 18E are each configured tointermesh with both the ring gear member 18B and the first set of planetgears 18D.

The planetary gear set 20 includes a sun gear member 20C, a ring gearmember 20A and a planet gear carrier member 20B that rotatably supportsa set of planet gears 20D (only one of which is shown). The sun gearmember 20C is connected for common rotation with a ninth shaft orinterconnecting member 60 and with a tenth shaft or interconnectingmember 62. The ring gear member 20A is connected for common rotationwith a fourth shaft or interconnecting member 48. The planet carriermember 20B is connected for common rotation with the seventh shaft orinterconnecting member 56 and with the output shaft or member 22. Theplanet gears 20D are each configured to intermesh with both the sun gearmember 20C and the ring gear member 20A.

The input shaft or member 12 is continuously connected to an engine (notshown) or to a turbine of a torque converter (not shown). The outputshaft or member 22 is continuously connected with the final drive unitor transfer case (not shown).

The torque-transmitting mechanisms or clutches 24, 26, 28 and brakes 30,32 and 34 allow for selective interconnection of the shafts orinterconnecting members, members of the planetary gear sets and thehousing. For example, the first clutch 24 is selectively engageable toconnect the eighth shaft or interconnecting member 58 with the tenthshaft or interconnecting member 62. The second clutch 26 is selectivelyengageable to connect the sixth shaft or interconnecting member 54 withthe tenth shaft or interconnecting member 62. The third clutch 28 isselectively engageable to connect the input shaft or member 12 with theninth shaft or interconnecting member 60. The first brake 30 isselectively engageable to connect the fourth shaft or interconnectingmember 48 with the stationary element or the transmission housing 50 inorder to restrict the member 48 from rotating relative to thetransmission housing 50. The second brake 32 is selectively engageableto connect the third shaft or interconnecting member 46 with thestationary element or the transmission housing 50 in order to restrictthe member 46 from rotating relative to the transmission housing 50. Thethird brake 34 is selectively engageable to connect the first shaft orinterconnecting member 42 with the stationary element or thetransmission housing 50 in order to restrict the member 42 from rotatingrelative to the transmission housing 50.

Referring now to FIG. 2 and FIG. 3, the operation of the ten speedtransmission 10 will be described. It will be appreciated thattransmission 10 is capable of transmitting torque from the input shaftor member 12 to the output shaft or member 22 in at least ten forwardspeed or torque ratios and at least one reverse speed or torque ratio.Each forward and reverse speed or torque ratio is attained by engagementof one or more of the torque-transmitting mechanisms (i.e. first clutch24, second clutch 26, third clutch 28, first brake 30, second brake 32and third brake 34), as will be explained below. FIG. 3 is a truth tablepresenting the various combinations of torque-transmitting mechanismsthat are activated or engaged to achieve the various gear states. An “X”in the box means that the particular clutch or brake is engaged toachieve the desired gear state. An “O” represents that the particulartorque transmitting device (i.e. a brake or clutch) is on or active, butnot carrying torque. Actual numerical gear ratios of the various gearstates are also presented although it should be appreciated that thesenumerical values are exemplary only and that they may be adjusted oversignificant ranges to accommodate various applications and operationalcriteria of the transmission 10. Of course, other gear ratios areachievable depending on the gear diameter, gear teeth count and gearconfiguration selected.

For example to establish a reverse gear, first clutch 24, first brake 30and third brake 34 are engaged or activated. The first clutch 24connects the eighth shaft or interconnecting member 58 with the tenthshaft or interconnecting member 62. The first brake 30 connects thefourth shaft or interconnecting member 48 with the stationary element orthe transmission housing 50 in order to restrict the member 48 fromrotating relative to the transmission housing 50. The third brake 34 thefirst shaft or interconnecting member 42 with the stationary element orthe transmission housing 50 in order to restrict the member 42 fromrotating relative to the transmission housing 50. Likewise, the tenforward ratios are achieved through different combinations of clutch andbrake engagement, as shown in FIG. 3.

It will be appreciated that the foregoing explanation of operation andgear states of the ten speed transmission 10 assumes, first of all, thatall the clutches not specifically referenced in a given gear state areinactive or disengaged and, second of all, that during gear shifts,i.e., changes of gear state, between at least adjacent gear states, aclutch engaged or activated in both gear states will remain engaged oractivated.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

The invention claimed is:
 1. A transmission comprising: an input member;an output member; first, second, third and fourth planetary gear setseach having first, second and third members, and wherein the inputmember is continuously connected for common rotation with one of themembers of the first planetary gear set and the output member iscontinuously connected for common rotation with one of the members ofthe fourth planetary gear set and one of the members of the thirdplanetary gear set; four interconnecting members continuouslyinterconnecting a member of the first, second, third and fourthplanetary gear sets with another member of the first, second, third andfourth planetary gear sets; and six torque transmitting mechanismswherein three of the six torque transmitting mechanisms are eachselectively engageable to interconnect at least one of the first, secondand third members of the first, second, third, and fourth planetary gearsets directly with at least one other of the first, second, thirdmembers of the first, second, third, and fourth planetary gear sets andwherein three of the six torque transmitting mechanisms are eachselectively engageable to interconnect at least one of the first, secondand third members of the first, second, third, and fourth planetary gearsets directly with a stationary member, and wherein the six torquetransmitting mechanisms are selectively engageable in combinations of atleast three to establish a plurality of forward speed ratios and atleast one reverse speed ratio between the input member and the outputmember, a first of the six torque transmitting mechanisms is selectivelyengageable to interconnect one of the members of the third planetarygear set directly with the third member of the fourth planetary gearset, and a second of the six torque transmitting mechanisms isselectively engageable to interconnect the input member directly withthe third member of the fourth planetary gear set.
 2. The transmissionof claim 1 wherein the four interconnecting members further comprises afirst interconnecting member continuously interconnecting the secondmember of the first planetary gear set with the third member of thethird planetary gear set, a second interconnecting member continuouslyinterconnecting the first member of the second planetary gear set withthe first member of the fourth planetary gear set, a thirdinterconnecting member continuously interconnecting the second member ofthe second planetary gear set with the first member of the thirdplanetary gear set, and a fourth interconnecting member continuouslyinterconnecting the second member of the third planetary gear set withthe second member of the fourth planetary gear set.
 3. The transmissionof claim 1 wherein the first of the six torque transmitting mechanismsis selectively engageable to interconnect the first member of the thirdplanetary gear set and the second member of the second planetary gearset with the third member of the fourth planetary gear set.
 4. Thetransmission of claim 3 wherein a third of the six torque transmittingmechanisms is selectively engageable to interconnect the third member ofthe third planetary gear set and the second member of the firstplanetary gear set with the third member of the fourth planetary gearset.
 5. The transmission of claim 4 wherein the second of the six torquetransmitting mechanisms is selectively engageable to interconnect thethird member of the first planetary gear set and the input member withthe third member of the fourth planetary gear set.
 6. The transmissionof claim 5 wherein a fourth of the six torque transmitting mechanisms isselectively engageable to interconnect the first member of the secondplanetary gear set with the stationary member.
 7. The transmission ofclaim 6 wherein a fifth of the six torque transmitting mechanisms isselectively engageable to interconnect the third member of the secondplanetary gear set with the stationary member.
 8. The transmission ofclaim 7 wherein a sixth of the six torque transmitting mechanisms isselectively engageable to interconnect the first member of the firstplanetary gear set with the stationary member.
 9. The transmission ofclaim 1 wherein the input member is continuously connected for commonrotation with the third member of the first planetary gear set.
 10. Thetransmission of claim 1 wherein the output member is continuouslyconnected for common rotation with the second member of the fourthplanetary gear set and the second member of the third planetary gearset.
 11. The transmission of claim 1 wherein the first member of thefirst planetary gear set, the third member of the second planetary gearset, the third member of the third planetary gear set and the thirdmember of the fourth planetary gear set are sun gears, the secondmembers of the first, second and fourth planetary gear sets and thefirst member of the third planetary gear set are carrier members and thethird member of the first planetary gear set, the first member of thesecond planetary gear set, the second member of the third planetary gearset and the first member of the fourth planetary gear set are ringgears.
 12. A transmission comprising: an input member; an output member;first, second, third and fourth planetary gear sets each having first,second and third members, and wherein the output member is continuouslyconnected for common rotation with one of the members of the fourthplanetary gear set and one of the members of the third planetary gearset; a first interconnecting member continuously interconnecting thesecond member of the first planetary gear set with the third member ofthe third planetary gear set; a second interconnecting membercontinuously interconnecting the first member of the second planetarygear set with the first member of the fourth planetary gear set; a thirdinterconnecting member continuously interconnecting the second member ofthe second planetary gear set with the first member of the thirdplanetary gear set; a fourth interconnecting member continuouslyinterconnecting the second member of the third planetary gear set withthe second member of the fourth planetary gear set; and six torquetransmitting mechanisms wherein three of the six torque transmittingmechanisms are each selectively engageable to interconnect at least oneof the first, second and third members of the first, second, third, andfourth planetary gear sets with at least one other of the first, second,third members of the first, second, third, and fourth planetary gearsets and wherein three of the six torque transmitting mechanisms areeach selectively engageable to interconnect at least one of the first,second and third members of the first, second, third, and fourthplanetary gear sets with a stationary member, and wherein the six torquetransmitting mechanisms are selectively engageable in combinations of atleast three to establish at least ten forward speed ratios and at leastone reverse speed ratio between the input member and the output member,a first of the six torque transmitting mechanisms is selectivelyengageable to interconnect one of the members of the third planetarygear set directly with the third member of the fourth planetary gearset, and a second of the six torque transmitting mechanisms isselectively engageable to interconnect the input member directly withthe third member of the fourth planetary gear set.
 13. The transmissionof claim 12 wherein first of the six torque transmitting mechanisms isselectively engageable to interconnect the first member of the thirdplanetary gear set and the second member of the second planetary gearset with the third member of the fourth planetary gear set.
 14. Thetransmission of claim 13 wherein a third of the six torque transmittingmechanisms is selectively engageable to interconnect the third member ofthe third planetary gear set and the second member of the firstplanetary gear set with the third member of the fourth planetary gearset.
 15. The transmission of claim 14 wherein the second of the sixtorque transmitting mechanisms is selectively engageable to interconnectthe third member of the first planetary gear set and the input memberwith the third member of the fourth planetary gear set.
 16. Thetransmission of claim 15 a fourth of the six torque transmittingmechanisms is selectively engageable to interconnect the first member ofthe second planetary gear set with the stationary member.
 17. Thetransmission of claim 16 wherein a fifth of the six torque transmittingmechanisms is selectively engageable to interconnect the third member ofthe second planetary gear set with the stationary member.
 18. Thetransmission of claim 17 wherein a sixth of the six torque transmittingmechanisms is selectively engageable to interconnect the first member ofthe first planetary gear set with the stationary member.
 19. Thetransmission of claim 12 wherein the input member is continuouslyconnected for common rotation with the third member of the firstplanetary gear set.
 20. The transmission of claim 12 wherein the outputmember is continuously connected for common rotation with the secondmember of the fourth planetary gear set and the second member of thethird planetary gear set.
 21. The transmission of claim 12 wherein thefirst member of the first planetary gear set, the third member of thesecond planetary gear set, the third member of the third planetary gearset and the third member of the fourth planetary gear set are sun gears,the second members of the first, second and fourth planetary gear setsand the first member of the third planetary gear set are carrier membersand the third member of the first planetary gear set, the first memberof the second planetary gear set, the second member of the thirdplanetary gear set and the first member of the fourth planetary gear setare ring gears.
 22. A transmission comprising: an input member; anoutput member; first, second, third and fourth planetary gear sets eachhaving a sun gear, a carrier member and a ring gear, wherein the inputmember is continuously connected for common rotation with the ring gearof the first planetary gear set, and wherein the output member iscontinuously connected for common rotation with the carrier member ofthe fourth planetary gear set and the ring gear of the third planetarygear set; a first interconnecting member continuously interconnectingthe carrier member of the first planetary gear set with the sun gear ofthe third planetary gear set; a second interconnecting membercontinuously interconnecting the ring gear of the second planetary gearset with the ring gear of the fourth planetary gear set; a thirdinterconnecting member continuously interconnecting the carrier memberof the second planetary gear set with the carrier member of the thirdplanetary gear set; a fourth interconnecting member continuouslyinterconnecting the ring gear of the third planetary gear set with thecarrier member of the fourth planetary gear set; a first torquetransmitting mechanism selectively engageable to interconnect thecarrier member of the third planetary gear set and the carrier member ofthe second planetary gear set with the sun gear of the fourth planetarygear set; a second torque transmitting mechanism selectively engageableto interconnect the sun gear of the third planetary gear set and thecarrier member of the first planetary gear set with the sun gear of thefourth planetary gear set; a third torque transmitting mechanismselectively engageable to interconnect the ring gear of the firstplanetary gear set and the input member with the sun gear of the fourthplanetary gear set; a fourth torque transmitting mechanism selectivelyengageable to interconnect the ring gear of the second planetary gearset with the stationary member; a fifth torque transmitting mechanismselectively engageable to interconnect the sun gear of the secondplanetary gear set with the stationary member; a sixth torquetransmitting mechanism selectively engageable to interconnect the sungear of the first planetary gear set with the stationary member, andwherein the torque transmitting mechanisms are selectively engageable incombinations of at least three to establish a plurality of forward speedratios and at least one reverse speed ratio between the input member andthe output member.